Most of the barrier naked-eye 3D technologies commonly applied at present employ twisted nematic (TN) barrier structure, the viewing angle of which is essentially identical to that of an ordinary TN display screen.
However, the display screen cooperates with a TN barrier structure generally is a wide view angle display screen employing a wide view angle technology, such as, in-plane switching (IPS) display, fringe field switching (FFS) display, or advanced super dimension switch (ADS) display. In a wide view angle display, the transmission axis of an upper polarizer sheet and a lower polarizer sheet are perpendicular to each other, and the alignment directions of an upper alignment layer (such as the alignment layer on a color filter substrate) and a lower alignment layer (such as the alignment layer on an array substrate) are opposite to each other, and the transmission axis of the lower polarizer sheet is parallel with the line, along which the alignment direction of the lower alignment layer is located. The pixel electrode in the pixel structure of the wide view angle display is usually strip-shaped. As to a single domain mode (all of the strips of a pixel electrode are parallel with each other), the strip-shaped pixel electrode is parallel with the line, along which the alignment direction of the lower alignment layer is located, and parallel with or perpendicular to a gate line. As to a double-domain mode, as illustrated in FIG. 1, the line along which the alignment direction (illustrated by the arrow in FIG. 1) of the lower alignment layer is located is parallel with the gate line, and the strip-shaped pixel electrode 2 is at an angle of generally 7°˜11° with respect to the line along which the alignment direction of the lower alignment layer is located.
These two display modes (TN and wide view angle technologies) possess certain difference in view of the transmission angle of the polarizer sheet, and generally, such angle difference is 45° (this angle is connected with the alignment direction of the alignment layer of a respective wide view angle display panel). As illustrated in FIG. 2, the solid arrow indicates the initial alignment direction of liquid crystal (that is, the alignment direction of the alignment layer), and the dotted arrow indicates the direction of the transmission axis of a polarizer sheet, and the dotted line indicates the direction of a light path. As can be seen from FIG. 2, the direction of the transmission axis of the polarizer sheet on the side of the light exiting surface of the wide view angle display possesses angle difference of 45° with respect to the direction of the transmission axis of the polarizer sheet at the light entering surface of the 3D grating.
In order for making the 3D grating match with the wide view angle display, that is, that the transmission axis of the upper polarizer sheet of the wide view angle display panel is parallel with the transmission axis of the lower polarizer sheet of the 3D grating, the transmission axis of the 3D grating (i.e., the adhesion direction of the polarizer sheet of the 3D grating, and the alignment direction of the alignment layer) is usually subjected to rotation of an angle of 45° so as to match with the direction of the transmission axis at the light exiting side of the wide view angle display. However, due to the rotation, the viewing angle of the 3D grating will departure from the optimal viewing direction for human eyes (which optimal direction is usually at the 6 clock direction, i.e., right ahead along a sight line), thus invoking bad viewing angle characteristics during 3D display.